An echo in this context just means whether if you send a simple message to a remote computer if you hear back. (Similar to ping/ICMP message).

EDIT: See Graham Hill's excellent comment below to disable this feature in chrome (In Settings, Under the Hood, uncheck "Automatically send usage statistics and crash reports to Google" or similar text.)

You should be able to turn this off by choosing Chrome > Preferences…, going to the Under the Hood section, and unchecking "Help make Google Chrome better by automatically sending usage statistics and crash reports to Google." (Windows and Linux users get to Under the hood via [Wrench menu] > Options) Google would prefer you leave it on, though, since these diagnostics are especially helpful for Beta, Dev, and Canary channel builds.
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Graham HillApr 27 '12 at 14:08